Isolation and characterization of two new herpes-like viruses from capuchin monkeys.

Two herpes-like viruses were isolated from capuchin monkey (Cebus apella) brain and (Cebus albifrons) spleen cell cultures, respectively. Both isolates induced similar cytopathic effects consisting of rounded and ballooned cells in the original monkey cell cultures and in a wide range of permissive cell types. Neutralizing antibody to each virus was present in serum from the capuchin monkey from which it was isolated, but the two viruses did not cross-react by neutralization. Fluorescein isothiocyanate conjugates of hyperimmune rabbit serum to one of the isolates showed an antigenic cross relationship between the two isolates. By electron microscopy, herpes-like virus particles were observed in the nucleus and cytoplasm of infected human diploid fibroblast cell cultures. Virus-infected cell cultures stained with acridine orange revealed small deoxyribonucleic acid-containing intranuclear inclusion bodies. Both viruses were inhibited by 5-fluorodeoxyuridine and inactivated by chloroform or exposure to 56 degrees C for 30 min. Antisera prepared against 16 prototype herpesviruses and cytomegaloviruses did not neutralize approximately 100 50% tissue culture infective doses of either capuchin isolate. Neutralizing antibody to the capuchin isolates was detected in sera from 8 of 17 capuchin monkeys but not in sera from 16 humans, 15 chimpanzees, and 10 spider, 6 rhesus, and 5 squirrel monkeys.